A ball is thrown 125 meters upward and then falls the same distance back to Earth. Neglecting air resistance, its total time in the air is
A) about 5 seconds.
B) about 15 seconds.
C) about 10 seconds.
D) more than 20 seconds.

Question

Quizplus · Accepted Answer

The total time in the air can be calculated using the formula $t = \frac{2v}{g}$, where $v$ is the initial velocity and $g$ is the acceleration due to gravity (approximately $9.8 m/s^2$). Since the ball travels 125 meters upward, we can use the motion equations to find the initial velocity required for such a displacement in a gravity field, and then calculate the total time. The time to go up will be the same as the time to come down, doubling the ascent time gives the total time. The correct calculation will show that the total time is about 10 seconds, considering the symmetry of the motion without air resistance.

A Ball Is Thrown 125 Meters Upward and Then Falls